English Amiga Board - View Single Post - Pacman - the Amiga conversion from the arcade game

Asman · 06 September 2019, 20:55

@jotd

Look here https://github.com/shaunlebron/pacma...isasm/bart.asm

In ancient times I also thought about perfect pacman port. And I thought about converter from Z80 --> mc68000. Of course I did nothing - just disasm some block of code and I stuck with z80 code.

Lets focus on simple z80 routine. (Code taken from bart.asm)

Code:

; ( rst 8 - Fill (HL)...(HL+B) with Accumulator )
[0x8] 8       0x77    LD (HL), A                  ;  Load location (HL) with Accumulator
[0x9] 9       0x23    INC HL                      ;  Increment register pair HL
[0xa] 10      0x10    DJNZ N          fc          ;  Decrement B and jump relative 0xfc (-4) if B!=0
[0xc] 12      0xc9    RET                         ;  Return

The converter should convert it in following way (assumption D0 = reg A, D1 - B, A3 - HL )

Code:

label08:	move.b	D0,(a3)		;label08:	0x77	->	ld	(hl),a
		addq.w	#1,a3		;		0x23	->	inc	hl
		dbf	d1,label08	;		0x10	0xfc	->	djnz	label08
		rts			;		0xc9	->	ret

Am I right or it just my imagination about perfect world ?

Of course its only idea. So first question which comes to my mind is about best usage of 68k registers for z80 register (mapping). How it usually done ?

edit: changed addq.b --> addq.w. Thanks to hitchhikr.

06 September 2019, 20:55	#3
Asman 68k Join Date: Sep 2005 Location: Somewhere Posts: 829	@jotd Look here https://github.com/shaunlebron/pacma...isasm/bart.asm In ancient times I also thought about perfect pacman port. And I thought about converter from Z80 --> mc68000. Of course I did nothing - just disasm some block of code and I stuck with z80 code. Lets focus on simple z80 routine. (Code taken from bart.asm) Code: ; ( rst 8 - Fill (HL)...(HL+B) with Accumulator ) [0x8] 8 0x77 LD (HL), A ; Load location (HL) with Accumulator [0x9] 9 0x23 INC HL ; Increment register pair HL [0xa] 10 0x10 DJNZ N fc ; Decrement B and jump relative 0xfc (-4) if B!=0 [0xc] 12 0xc9 RET ; Return The converter should convert it in following way (assumption D0 = reg A, D1 - B, A3 - HL ) Code: label08: move.b D0,(a3) ;label08: 0x77 -> ld (hl),a addq.w #1,a3 ; 0x23 -> inc hl dbf d1,label08 ; 0x10 0xfc -> djnz label08 rts ; 0xc9 -> ret Am I right or it just my imagination about perfect world ? Of course its only idea. So first question which comes to my mind is about best usage of 68k registers for z80 register (mapping). How it usually done ? edit: changed addq.b --> addq.w. Thanks to hitchhikr. Last edited by Asman; 06 September 2019 at 23:03.